US8033652B2 - Liquid discharge head and recording apparatus having the same - Google Patents

Liquid discharge head and recording apparatus having the same Download PDF

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US8033652B2
US8033652B2 US12/416,844 US41684409A US8033652B2 US 8033652 B2 US8033652 B2 US 8033652B2 US 41684409 A US41684409 A US 41684409A US 8033652 B2 US8033652 B2 US 8033652B2
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liquid
ink
liquid chamber
bubbles
introduction passage
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US20090244181A1 (en
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Ryoichiro Kurobe
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Canon Inc
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Canon Inc
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    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/17—Ink jet characterised by ink handling
    • B41J2/175—Ink supply systems ; Circuit parts therefor
    • B41J2/17503—Ink cartridges
    • B41J2/17513—Inner structure
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2/00—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed
    • B41J2/005—Typewriters or selective printing mechanisms characterised by the printing or marking process for which they are designed characterised by bringing liquid or particles selectively into contact with a printing material
    • B41J2/01—Ink jet
    • B41J2/135—Nozzles
    • B41J2/14—Structure thereof only for on-demand ink jet heads
    • B41J2/14016—Structure of bubble jet print heads
    • B41J2/14145—Structure of the manifold
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B41—PRINTING; LINING MACHINES; TYPEWRITERS; STAMPS
    • B41J—TYPEWRITERS; SELECTIVE PRINTING MECHANISMS, i.e. MECHANISMS PRINTING OTHERWISE THAN FROM A FORME; CORRECTION OF TYPOGRAPHICAL ERRORS
    • B41J2202/00—Embodiments of or processes related to ink-jet or thermal heads
    • B41J2202/01—Embodiments of or processes related to ink-jet heads
    • B41J2202/07—Embodiments of or processes related to ink-jet heads dealing with air bubbles

Definitions

  • the present invention relates to a liquid discharge head that ejects liquid, such as ink, and a recording apparatus having the same.
  • a known example of a liquid discharge head is an inkjet recording head (hereinafter referred to as a recording head).
  • the recording head is provided with a recording element substrate for ejecting liquid such as ink. Recording is performed such that ink held and stored in an ink tank is supplied to the recording element substrate through an ink supply channel.
  • a recording element substrate to which the more than one kind of ink is supplied is mounted to a recording head.
  • efforts are being made to reduce the areas of, particularly, the high-cost recording element substrates.
  • a recording element substrate H 1101 has a plurality of discharge port arrays H 1108 (one discharge port group corresponding to one ink supply port is defined as one discharge port array) at predetermined intervals.
  • An increase in cost due to an increase in the area of a recording element substrate is prevented by decreasing the distance between the discharge port arrays (between colors).
  • Ink supply ports H 1102 are formed in correspondence with the discharge port arrays H 1108 , respectively.
  • FIG. 14A shows an external view of an ink-tank integral-type recording head disclosed in U.S. Patent Laid-Open No. 2005-0285904, and FIG. 14B shows the internal structure thereof.
  • an ink-tank integral-type recording head H 1000 capable of supplying more than one kind of ink includes a plurality of ink containing portions H 2001 to H 2003 for holding ink.
  • FIGS. 15A and 15B are sectional views of the recording head H 1000
  • FIGS. 16A to 16C are diagrams for describing the shape of an ink supply path.
  • FIG. 15A shows a perspective view of a section of an ink tank H 1500 cut along the ink supply path S 01 ;
  • FIG. 15B shows an enlarged view of a part XVB of the perspective sectional view.
  • ink contained in the ink containing portion H 2001 passes through an ink introduction passage H 2101 through a filter H 1701 and passes through a liquid chamber H 2201 to reach the ink supply port H 1102 .
  • a plurality of discharge ports is equally supplied with ink from the liquid chambers.
  • an ink supply path in this specification indicates a part constituted by “an ink introduction passage” serving as a liquid introduction passage and “a liquid chamber”, and the connecting portion between the ink introduction passage and the liquid chamber is referred to as a communicating portion C.
  • FIG. 16B is a diagram showing the ink supply paths S 01 to S 02 and the recording element substrate H 1101 corresponding to the recording head H 1000 .
  • liquid chambers H 2201 to H 2203 which are part of the individual ink supply paths S 01 to S 03 are arranged parallel in correspondence with the individual ink supply ports H 1102 . Accordingly, as shown in FIG.
  • the liquid-chamber width W of at least the inner ink supply path S 01 is generally set, at about 0.6 to 0.8 mm, in agreement with the width W′ of the ink supply port H 1102 (see FIG. 12 ) because the distances between the individual colors are short.
  • ink in ink supply paths or the like contains gas (dissolved gas) dissolved in the ink and external gas that passes through an ink tank formed from polymer or the like. If these gases are turned into bubbles in liquid chambers, the bubbles sometimes remain in the liquid chambers for a long time until the bubbles pass into the ink introduction passages that are wider in the y-direction than the liquid chambers or are sometimes left in the liquid chambers. This is because bubbles hardly move in the liquid chambers because the liquid-chamber width W is small. Thus, if bubbles remain or are left in the liquid chambers for a long time, they can exert a bad influence on recording.
  • gas dissolved gas
  • the bubbles are generally removed by, for example, joining a member called a cap to the discharge-port formed surface of a recording head, and reducing the pressure inside the cap with a pump or the like to apply a sucking force (suction recovery, U.S. Pat. No. 6,722,757).
  • a possible method for solving the problem is to reduce the frequency of suction recovery by increasing the liquid-chamber width W so as to prevent bubbles from staying in the liquid chambers so that the presence of bubbles in the liquid chambers does not easily exert a bad influence on recording.
  • the liquid chambers H 2201 to H 2203 are arranged parallel in correspondence with the ink supply ports H 1102 , so that the width W ( FIG. 16C ) of at least the inner liquid chamber H 2201 cannot be increased because of the presence of the other liquid chambers H 2202 and H 2203 on either side.
  • Another possible method is to increase the liquid-chamber width W by increasing the distance between the ink supply ports H 1102 . This is, however, not desirable, because this increases the area of the recording element substrate, thus increasing the cost.
  • bubbles B exhibit the behavior shown in FIGS. 17A to 17F . That is, the bubbles B are generated at the ends of the liquid chambers ( FIG. 17A ), continue to grow while staying at the ends ( FIGS. 17B to 17D ), quickly move toward the communicating portion C due to vibrations or the like ( FIG. 17E ), and at the communication part C, the ink flow is substantially blocked ( FIG. 17F ). Vibrations are generated when the recording head is mounted or the ink tank is mounted.
  • a possible method for solving such problems is to increase the x-direction length Cx ( FIG. 16A ) of the communicating portion C so that the ink flow is not blocked at the communicating portion C.
  • the inner ink supply path S 01 cannot sometimes have sufficient Cx because of limitations due to the positional relationship among the ink supply paths S 01 to S 03 .
  • the present invention provides an inkjet recording head capable of stable recording even if bubbles are generated in a liquid chamber.
  • a liquid discharge head includes a discharge port array, having a plurality of discharge ports configured to discharge liquid; a liquid chamber configured to supply liquid to the discharge port array, wherein a vertical cross section of the liquid chamber has an elongated shape of which a length direction is along the discharge port array, in a state in which the head is mounted to the apparatus; and a liquid introduction passage configured to introduce liquid to the liquid chamber, the liquid introduction passage being wider than the liquid chamber in a width direction of the elongated shape; wherein a communicating portion in which the liquid chamber communicate with the liquid introduction passage is longer than a width of the liquid chamber along the width direction and shorter than the liquid chamber, with respect to the length direction, and is projecting from the liquid introduction passage for the liquid chamber, wherein with respect to a vertical direction in the state, a bottom of the liquid introduction passage is disposed at lower position than a top of the liquid chamber in the communicating portion, and a distance between the top and the bottom is longer than half of the width of the liquid chamber.
  • bubbles can easily communicate through the communicating portion between the liquid introduction passage and the liquid chamber, so that the bubbles can easily move from the liquid chamber to the liquid introduction passage. Accordingly, a liquid discharge head can be provided in which the influence of the bubbles in the liquid chamber on recording can be reduced so that stable recording can be performed.
  • FIGS. 1A through 1E are diagrams for describing the behavior of bubbles in an ink supply path.
  • FIGS. 2A through 2C are diagrams for describing the behavior of bubbles in an ink supply path according to an embodiment of the present invention.
  • FIGS. 3A through 3C are diagrams for describing the behavior of bubbles in an ink supply path of a comparative example.
  • FIG. 4A is a diagram showing an ink supply path according to an embodiment of the present invention in which the liquid chamber has inclined surfaces.
  • FIGS. 4B and 4C are diagrams showing ink supply paths of comparative examples in which the liquid chambers have inclined surfaces.
  • FIG. 5A is a sectional view of an ink tank of a first embodiment.
  • FIG. 5B is an enlarged view of an ink supply path in FIG. 5A .
  • FIG. 6A is a diagram for describing an ink supply path of the first embodiment.
  • FIG. 6B is a diagram for describing the behavior of bubbles in an ink supply path by comparing the first embodiment and a comparative example.
  • FIG. 6C is a schematic perspective view of the ink supply path shown in FIG. 6A .
  • FIG. 7A is a diagram for describing an ink supply path of a second embodiment.
  • FIG. 7B is a schematic perspective view of the inner ink supply path shown in FIG. 7A and outer ink supply paths in an ink tank.
  • FIG. 7C is a diagram for describing the behavior of bubbles in one of the outer ink supply paths shown in FIG. 7B .
  • FIG. 8A is a sectional view of an ink tank according to a third embodiment.
  • FIG. 8B is an enlarged view of an ink supply path in FIG. 8A .
  • FIG. 9A is a diagram for describing an ink supply path according to the third embodiment.
  • FIG. 9B is a diagram for describing the behavior of bubbles in an ink supply path by comparing the third embodiment and a comparative example.
  • FIG. 9C is a schematic perspective view of the inner ink supply path shown in FIG. 9A and outer ink supply paths in an ink tank.
  • FIGS. 10A and 10B are diagrams showing an inkjet recording head incorporating the ink supply paths of the first and second embodiments of the present invention.
  • FIG. 11 is a diagram showing an inkjet recording head incorporating the ink supply paths of the third embodiment of the present invention.
  • FIG. 12 is a diagram for describing a recording element substrate.
  • FIG. 13 is a diagram showing an example of an inkjet recording apparatus.
  • FIGS. 14A and 14B are diagrams for describing a conventional inkjet recording head.
  • FIG. 15A is a sectional view of a conventional ink tank.
  • FIG. 15B is an enlarged view of an ink supply path in FIG. 15A .
  • FIGS. 16A through 16C are diagrams for describing ink supply paths in a conventional ink tank.
  • FIGS. 17A through 17F are schematic diagrams for describing the generation and growth of bubbles in ink supply paths.
  • FIGS. 10A to 12 are diagrams for describing an inkjet recording head serving as a liquid discharge head according to an embodiment of the present invention. The components thereof will be described hereinbelow with reference to the drawings.
  • “recording” indicates either of forming significant information such as characters and graphics and visualizing either significant or insignificant information so that human beings can visually perceive it. It also broadly includes forming an image, a design, a pattern, etc. on a recording medium and processing a medium.
  • a recording medium includes not only paper used in common recording apparatuses but also ink-acceptable materials, such as cloth, plastic film, a metal plate, glass, ceramic, lumber, and leather.
  • “Ink” (sometimes referred to as “liquid”) should be broadly defined as for the above-described “recording”. That is, “ink” includes liquid for use in forming an image, a design, or a pattern or processing a recording medium, or processing ink (for example, solidifying or insolubilizing a coloring material in ink applied to a recording medium). Thus, “ink” in this specification includes all forms of liquid that can be used for printing.
  • a liquid discharge head that can incorporate the present invention is an inkjet recording head (recording head) that uses an electrothermal converter for making liquid, such as ink, cause film boiling in liquid, such as ink, in response to an electrical signal.
  • the electrothermal converter is disposed so as to face an ink discharge port.
  • FIG. 10A shows a recording head H 1001 that can incorporate the present invention.
  • FIG. 10B shows exploded perspective views of the recording head H 1001 .
  • the recording head H 1001 is of an ink-tank integrated type and has a form that can contain a plurality of kinds of ink, for example, color inks (cyan ink, magenta ink, and yellow ink).
  • the recording head H 1001 is constituted by at least a recording element substrate H 1101 , an electrical wiring sheet H 1301 serving as an electrical wiring member, and an ink tank H 1501 serving as an ink holding member.
  • Another recording head H 1002 that can contain four kinds of ink has the same form as the recording head H 1001 , except that it has an ink tank H 1502 having a different inner configuration therefrom, as shown in exploded perspective views of FIG. 11 . Therefore, in FIG. 11 , descriptions of components denoted by the same reference numerals as in FIG. 10B will be omitted.
  • FIG. 12 is a diagram for describing the configuration of the recording element substrate H 1101 in fragmentary perspective view.
  • the recording element substrate H 1101 is constituted by a silicon substrate H 1110 having ink supply ports H 1102 , electrothermal converters H 1103 , electric cables, an electrode portion H 1104 and so on, and ink channel walls H 1106 and discharge ports H 1107 formed on the silicon substrate H 1110 .
  • the ink channel walls H 1106 and the discharge ports H 1107 are formed of a polymer material on the silicon substrate H 1110 by photolithography technology.
  • Bumps H 1105 made of gold or the like are formed on the electrode portion H 1104 for supplying electrical signals and electricity for driving the electrothermal converters H 1103 .
  • the recording element substrate H 1101 that can eject three kinds of ink has three parallel ink supply ports H 1102 , for cyan, magenta, and yellow, for example.
  • the electrothermal converters H 1103 and the discharge ports H 1107 are disposed in line on either side of the individual ink supply ports H 1102 .
  • a recording element substrate (not shown) that can eject four kinds of ink has four parallel ink supply ports for cyan, magenta, yellow, and black, for example, like the recording element substrate H 1101 .
  • the electrical wiring sheet H 1301 shown in FIG. 10B has an electrical-signal path for applying electrical signals for ejecting ink onto the recording element substrate H 1101 and is constructed by forming a copper-foil wiring pattern on a polyimide base substrate.
  • the electrical wiring sheet H 1301 further has external-signal input terminals H 1302 for receiving electrical signals from a main-body apparatus.
  • the ink tank H 1501 serving as a liquid holding member, shown in FIG. 10B is formed by molding polymer.
  • the polymer material it is preferable to use a polymer material mixed with 5-40% glass filler to improve the rigidity of the ink tank H 1501 .
  • the recording element substrate H 1101 is bonded in accurate position to the ink tank H 1501 , at the downstream part of the ink supply paths provided in the ink tank H 1501 , so as to allow ink to communicate with the ink supply ports H 1102 formed in the recording element substrate H 1101 .
  • the back surface of part of the electrical wiring sheet H 1301 is bonded by an adhesive to the flat surface around the recording element substrate H 1101 .
  • the electrically connected portion between the recording element substrate H 1101 and the electrical wiring sheet H 1301 is protected from corrosion due to ink and an external impact by being sealed with a sealant.
  • An unbonded portion of the electrical wiring sheet H 1301 is bent and fixed by thermal caulking or with an adhesive or the like to a side surface that is substantially perpendicular to the surface of the ink tank H 1501 on which liquid chambers H 2211 to H 2213 are formed (the surface on which the recording element substrate H 1101 is bonded).
  • a concrete configuration of the ink supply paths for supplying ink from the ink tank H 1501 to the recording element substrate H 1101 will be described in detail in embodiments, to be described later.
  • the ink supply path is configured such that ink communicates through the connected portion between the ink introduction passage and the liquid chamber and that the ink introduction passage is located vertically above (in the z-direction) of the liquid chamber during use of the recording head, stated differently, in a state in which the recording head is mounted to a recording apparatus (See FIG. 13 ).
  • a vertical cross section of the liquid chamber is an elongated shape, and the length direction of the elongated shape is defined as an x-direction and the width direction thereof is defined as a y-direction.
  • the cross section of the end of the bubbles B that are not in contact with the walls of the liquid chamber is expected to form a substantially semicircular shape, the curvature radius rb of which seems to depend on the liquid-chamber width W (the length in the y-direction). Accordingly, the curvature radius rb of the cross section of the end of the bubbles B can be approximated to W/2 ( FIG. 1C ). This will be described later in detail.
  • the bubbles B are acted on by buoyancy, Fbuoyancy, vertically upward (in the z-direction) due to the difference in density between liquid and gas and by a force, vertically downward, that prevents the movement of the bubbles B.
  • the force that prevents the movement of the bubbles B is caused by the contact of the bubbles B with the walls of the liquid chamber.
  • This force is referred to as adhesive force, Fadhesion.
  • the adhesive force Fadhesion seems to depend on the surface tension of liquid, the liquid-chamber width W, and the contact area between the bubbles B and the walls of the liquid chamber. That is, the adhesive force Fadhesion is expected to increase when the surface tension of the liquid is large, when the width W of the liquid chamber is small, and when the contact area is large.
  • the bubbles B located at the position shown in FIG. 1A move upward in a liquid chamber 300 ( FIG. 1B ).
  • the part (hereinafter referred to as a bubble adhering portion) of the bubbles B that is in contact with the walls of the liquid chamber 300 reaches the communicating portion C ( FIG. 1B ).
  • the bubble adhering portion reaches the communicating portion C, the bubbles B communicate through the communicating portion C into an ink introduction passage 200 that is larger in width in the y-direction than the liquid chamber 300 ( FIG. 1C ).
  • the adhesive force is expected to be reduced while the buoyancy Fbuoyancy is maintained. Accordingly, once the bubbles B start to communicate, the bubbles B can move toward the ink introduction passage 200 in a shorter time than during moving in the liquid chamber 300 . The bubbles B are expected to continue to move toward the ink introduction passage 200 without being separated until the buoyancy of the bubbles B in the ink introduction passage 200 becomes larger than the adhesive force in the liquid chamber 300 . Whether the bubbles B in the ink introduction passage 200 are separated from the bubbles B in the liquid chamber 300 seems to depend on the size of the bubbles B.
  • the bubbles B are in contact with the walls of the liquid chamber 300 , when the bubbles B move upward due to the buoyancy in the liquid chamber 300 , adhesive force in addition to the buoyancy is applied to the bubbles B. Accordingly, unless vibrations or the like are applied to the liquid chamber 300 , the bubbles B having many adhering portions on the walls of the liquid chamber 300 can move only at a significantly slow speed.
  • the influence of the bubbles B on recording is large because the ratio of the volume of the liquid chamber 300 to the volume of the bubbles B is high and the liquid chamber 300 is close to the ink supply port. Accordingly, it is important to move the bubbles B from the liquid chamber 300 to the ink introduction passage 200 .
  • the reason why the curvature radius rb can be approximated to W/2 will be described with reference to FIG. 1D .
  • the bubbles B move upward in the liquid chamber 300 that is wet with liquid such as ink.
  • liquid such as ink.
  • the adhering portion of the bubbles B in the moving direction seems to be wet with the liquid.
  • the bubbles B are in contact with the walls of the liquid chamber 300 with thin liquid film therebetween.
  • the end of the bubbles B forms a free curved surface, so that the cross section of the end of the bubbles B on a surface perpendicular to the x-direction forms a semicircular shape, and therefore the curvature radius rb of the cross section of the end of the bubbles B can be approximated to W/2.
  • the shape of the cross section of the end of the bubbles B depends on the surface tension of the liquid and the width W of the liquid chamber 300 .
  • the curvature radius of the cross section of the end of the bubbles B is larger than the curvature radius rb, so that the end of the bubbles B (the part of the bubbles B that is not in contact with the walls of the liquid chamber 300 ) is smaller than that when the walls of the liquid chamber 300 are wet ( FIG. 1D ).
  • the adhesive force is large when the walls of the liquid chamber 300 are not wet than when wet, so that the bubbles B are expected to be hardly peeled off from the walls of the liquid chamber 300 .
  • FIGS. 2A to 2C show an ink supply path 110 as an example of the present invention
  • FIGS. 3A to 3C show the ink supply path 100 as a comparative example
  • FIGS. 2A and 3A are projection drawings as viewed from the z-direction
  • FIGS. 2B and 3B are projection drawings as viewed from the y-direction
  • FIG. 2C shows a K-K cross section and an L-L cross section (a plane including the y-axis and the z-axis) of FIG. 2B
  • FIG. 3C shows an M-M cross section (a plane including the y-axis and the z-axis) of FIG. 3B .
  • a boundary that increases in width in the y-direction from the liquid chamber to the ink introduction passage is referred to as a communicating portion C.
  • the communicating portion C is projecting from the liquid introduction passage for the liquid chamber.
  • the communicating portion C is indicated by a dotted line.
  • configurations as prerequisites of the present invention are that the relation between an ink introduction passage 210 and a liquid chamber 310 holds (1), for the x-direction, the length of the liquid chamber>the length Cx of the ink introduction passage at the communicating portion C>the width W of the liquid chamber and (2) for the y-direction, the length of the ink introduction passage>the length of the liquid chamber (the liquid-chamber width W) at the communicating portion C.
  • the relational expression of the left side and the middle side of (1) indicates a case in which the problem of the present invention that the ink flow is prone to be blocked at the communicating portion C by the bubbles B occurs. Satisfying the relational expression between the middle side and the right side of (1) and the relational expression (2) provides a configuration in which the bubbles B can easily move in the ink introduction passage than in the liquid chamber by increasing at least the lengths of the ink introduction passage in the x-direction and the y-direction than the liquid-chamber width W as much as possible.
  • the ink introduction passage has only to have lengths in the x-direction and the y-direction so as not to prevent the expansion of the bubbles B in the ink introduction passage when the bubbles B move to the ink introduction passage through the communicating portion C. Accordingly, the ink introduction passage may be configured to increase in length in the x-direction and the y-direction vertically upward from the communicating portion C.
  • Both of the present invention ( FIGS. 2A to 2C ) and the comparative example ( FIGS. 3A to 3C ) have an overlapping area Roverlap ( FIGS. 2A and 3A ) at the communicating portion C when the ink introduction passage is viewed from the z-direction.
  • the present invention when viewed from the x-direction, has the overlapping area Roverlap ( FIG. 2C ) of the communicating portion C, whereas the comparative example ( FIG. 3C ) has no overlapping area Roverlap of the communicating portion C.
  • a top T 310 of the liquid chamber 310 is located vertically above a bottom B 210 of the ink introduction passage 210 .
  • the bubbles B that have protruded in the x-direction from the communicating portion C receive a vertical drag from the walls at the top of the liquid chamber 300 .
  • the force applied to the bubbles B in this state includes buoyancy in a vertically upward direction and adhesive force and vertical drag in the vertically downward direction, which are balanced. Accordingly, with the configuration of the comparative example, the bubbles B stay in the vicinity of the communicating portion C, thus making it difficult to move the bubbles B to the ink introduction passage 200 through the communicating portion C.
  • the configuration of the present invention allows communication of the bubbles B to be induced even if bubbles B longer than Cx reach the communicating portion C.
  • the area of the ink communicating portions Cink in the present invention is larger than that of the comparative example. Therefore, the ink flow in the communicating portion C is more with the configuration of the present invention than with the configuration of the comparative example.
  • Cz is the z-direction length of the projection plane of the communicating portion C as viewed from the x-direction, which is the distance between the top T 310 of the liquid chamber 310 and the bottom B 210 of the ink introduction passage 210
  • rb is the curvature radius of the end of the bubbles B.
  • an ink supply path 110 a constituted by an ink introduction passage 210 a and a liquid chamber 310 a shown in FIG. 4A
  • the advantages of the present invention can be offered provided that the relation Cz>W/2 is satisfied. That is, since the bubbles B are along the inclined surfaces at an inclination angle ⁇ , as shown in FIG. 4A , the top of the bubbles B can protrude to the ink introduction passage 210 a .
  • the top of the adhering portion of the bubbles B can communicate with the ink introduction passage 210 a along a surface (a projection surface in the vertical direction) perpendicular to the vertical direction of the communicating portion C.
  • the top of the adhering portion of the bubbles B cannot always reach the ink supply path 100 a although the top of the bubbles B can protrude to the ink introduction passage 200 a .
  • a liquid chamber having an inclined surface may be configured such that either only one end has an inclined surface or both ends have an inclined surface.
  • the both ends may have different inclination angles.
  • the use of the configuration of the present invention can decrease the influences of bubbles on recording as compared with the configuration of the comparative examples.
  • FIGS. 5A , 5 B, 6 A, 6 B, 6 C, and 10 B A first embodiment will be described with reference to FIGS. 5A , 5 B, 6 A, 6 B, 6 C, and 10 B.
  • this embodiment has therein ink containing portions H 2011 to H 2013 for holding cyan, magenta, and yellow inks, like common inkjet recording heads, and independent ink supply paths for introducing the inks into the individual ink supply ports H 1102 in the recording element substrate H 1101 .
  • FIG. 5A is a perspective view of a cross section of the ink tank H 1501 (a covering member H 1901 and so on are not shown for clarification of description).
  • FIG. 5B shows an enlarged view of a part VB in FIG. 5A to describe the shape of the ink supply path of this embodiment in detail.
  • the connecting portion between a liquid chamber H 2211 having a given width W and an ink introduction passage H 2111 that is shorter than the length of the liquid chamber H 2211 and longer than the liquid-chamber width W in the x-direction is referred to as a communicating portion C.
  • the communicating portion C is constituted by one surface (including the x-axis and the y-axis) facing the ink supply port H 1102 and two surfaces (perpendicular to the x-direction) perpendicular to the surface and along the width direction of the liquid chamber H 2211 .
  • FIG. 6A is a schematic sectional view of an ink supply path S 11
  • FIG. 6C is a schematic perspective view of the ink supply path S 11 .
  • the surface (horizontal surface) facing the ink supply port H 1102 has a x-direction length Cx 1 (3.2 mm) and the two surfaces (vertical surfaces) along the width direction of the liquid chamber H 2211 has a z-direction length Cz 1 (1.4 mm).
  • the liquid chamber H 2211 has inclined surfaces at an inclination angle ⁇ so that bubbles generated at the ends of the liquid chamber H 2211 can easily move to the communicating portion C.
  • FIG. 6B schematically shows the ink supply paths of the embodiment of the present invention and the comparative example, showing the difference therebetween.
  • the moving distance of bubbles in the liquid chamber per unit time can be regarded as being equal provided that they have the same liquid-chamber width W and cone angle.
  • the communicating portion C has not only a horizontal surface but also vertical surfaces, bubbles can move to the ink introduction passage by a moving amount in the z-direction on the horizontal surface and a moving amount in the x-direction on the vertical surfaces.
  • the communicating portion C is constituted only by the horizontal surface, the bubbles can move to the ink introduction passage by only a moving amount in the z-direction.
  • bubbles communicate with the ink introduction passage H 2111 along one of the two vertical surfaces of the communicating portion C. Accordingly, an ink communication state is maintained at least on the other vertical surface or the horizontal surface until most of the bubbles move from the liquid chamber H 2211 to the ink introduction passage H 2111 .
  • the communicating portion C includes only the horizontal surface. Therefore, the area of communication of ink on the horizontal surface is small until bubbles communicate on the horizontal surface and most of the bubbles move to the ink introduction passage.
  • this embodiment has the advantage that bubbles generated in the liquid chamber easily communicate through the communicating portion C, so that they easily move from the liquid chamber to the ink introduction passage.
  • This embodiment also has the advantage that, since bubbles communicate to the ink introduction passage along any of the surfaces constituting the communicating portion C, an ink communicating state can be maintained on the other surfaces.
  • FIGS. 7A to 7C A second embodiment that is a modification of the first embodiment will be described with reference to FIGS. 7A to 7C .
  • the communicating portion C has an ink supply path S 21 , the height Cz of the vertical surfaces of which is shorter than that of the first embodiment.
  • the length Cx 2 is 3.4 mm. If the length Cx is longer than the height Cz as described above, bubbles can easily communicate along the horizontal surface of the communicating portion C.
  • This configuration provides the advantage that bubbles generated in the liquid chamber can easily communicate through the communicating portion C and can easily move from the liquid chamber to the ink introduction passage. Furthermore, as in the first embodiment, bubbles communicate to the ink introduction passage along any of the surfaces that constitute the communicating portion C, thus offering the advantages of allowing the ink communicating state of the other surface to be maintained.
  • the configuration of the inner ink supply path S 21 has been described. Next, the other ink supply paths will be specifically described with reference to FIG. 7B .
  • the ink supply paths of the first embodiment also have the same configuration as the ink supply paths to be described below.
  • FIG. 7B shows three ink supply paths S 21 to S 23 disposed appropriated in the ink tank H 1501 shown in FIG. 10B .
  • the disposition of a plurality of ink supply paths allows supply of a plurality of colors of ink while preventing upsizing of the recording head.
  • the ink supply path S 23 shown in FIG. 7B can be increased in the x-direction width Cx′ 2 of the communicating portion (equal to the x-direction length of the liquid chamber at the maximum).
  • Setting the difference Cz′ 2 between the tops of the wall surfaces of the liquid chamber to be larger than W/2, as shown by the O-O cross section of FIG. 7B , shown in FIG. 7C can provide a configuration in which bubbles can communicate more easily. Such a configuration allows the ink communication state to be maintained even if grown bubbles reach the communicating portion.
  • FIGS. 8A , 8 B, 9 A, 9 B, 9 C, and 11 A third embodiment will be described with reference to FIGS. 8A , 8 B, 9 A, 9 B, 9 C, and 11 .
  • first and second embodiments have been described as related to the configuration of an inkjet recording head having a recording element substrate capable of ejecting three colors of ink
  • the third embodiment will be described as related to a four-color inkjet recording head.
  • ink supply paths applied to the recording head H 1002 capable of ejecting four colors of ink, shown in FIG. 11 will be described.
  • the ink tank H 1502 has therein ink containing portions H 2031 to H 2034 for holding cyan, magenta, yellow, and black inks.
  • the ink supply ports in a recording element substrate (not shown) having four discharge port arrays have independent ink supply paths for introducing the inks into the individual ink supply ports.
  • FIG. 9C shows an example in which four ink supply paths S 31 to S 34 are appropriately arranged in the ink tank H 1502 shown in FIG. 11 .
  • the main difference between the first and second embodiments is the inner ink supply paths S 31 and S 33 .
  • the configuration of the inner ink supply path S 31 will be described in detail with reference to FIGS. 8A and 8B . Since the configuration of the ink supply path S 33 is substantially the same and has the same advantages, a description thereof will be omitted.
  • FIG. 8A is a perspective view of a cross section of the ink tank H 1502 (the covering member H 1901 and so on are not shown for clarification of description).
  • FIG. 8B is an enlarged view of a part VIIIB in FIG. 8A to describe in detail the shape of the ink supply path of this embodiment.
  • the communicating portion C of this embodiment is constituted by two surfaces, that is a horizontal surface and a vertical surface.
  • the ink supply path S 31 is constituted by an ink introduction passage H 2131 and a liquid chamber H 2231 .
  • the x-direction length of the horizontal surface of the communicating portion C, described above, is Cx 3 (3.1 mm)
  • the z-direction length of the vertical surface is Cz 3 (1.4 mm).
  • the configuration of the embodiment of the present invention allows an ink communicating state to be maintained on the vertical surface while the bubbles communicate along the horizontal surface. If the bubbles communicate along the vertical surface, the ink communicating state can be maintained on the horizontal surface. In contrast, in the comparative example, when bubbles reaches the communicating portion C constituted only by the horizontal surface, little ink communicates while the bubbles are communicating along the horizontal surface.
  • this embodiment is configured such that the inclination angle of the inclined surface of the liquid chamber can easily be increased as compared with the configurations of the first and second embodiments, the speed at which bubbles move in the z-direction in the liquid chamber can be increased, thus making the bubbles easily reach the communicating portion C.
  • the communicating portion C is constituted by two surfaces, bubbles can easily communicate through the communicating portion C, as in the first and second embodiments, and furthermore, an ink communicating state can be maintained on at least one surface.
  • surfaces to which the ink introduction passage and the liquid chamber connect may not necessarily be vertical or horizontal.
  • Surfaces that constitute the communicating portion C may be two or more. That is, it is sufficient that the communicating portion C have a projection plane viewed from the x-direction and a projection plane viewed from the x-direction, and the z-direction length of the projection plane viewed from the x-direction is larger than 1 ⁇ 2 of the liquid-chamber width W.
  • the ink introduction passage Although bubbles that have passed through the communicating portion C are stored in the ink introduction passage, the bubbles stored in that part can sometimes hardly be removed by suction recovery. Accordingly, it is preferable that the ink introduction passage have a sufficient volume not to affect on recording.
  • FIG. 13 is a schematic top view of an example of a recording apparatus on which the recording head according to an embodiment of the present invention can be mounted, showing the interior thereof.
  • this recording apparatus has a carriage 102 on which the recording heads shown in FIGS. 10A , 10 B, and 11 are located and replaceably mounted.
  • the carriage 102 has an electrically connecting portion for transferring electrical signals and so on to the individual electrothermal converters through the external-signal input terminals H 1302 ( FIGS. 10B and 11 ) provided on the individual electrical wiring sheets H 1301 ( FIGS. 10B and 11 ) that constitute the individual recording heads.
  • the carriage 102 also has mounting guide rails (not shown) corresponding to cover guides H 1902 ( FIGS. 10B and 11 ) provided at the covering member H 1901 .
  • the recording heads can be mounted, along the mounting guide rails, on the carriage 102 by supporting the cover guides H 1902 by the mounting guide rails.
  • the ink tanks that constitute the individual recording heads each have mounting guides H 1560 ( FIGS. 10B and 11 ) for guiding the recording heads to the head mounting positions of the carriage 102 .
  • the recording heads H 1001 and H 1002 are guided to predetermined positions of the carriage 102 by the mounting guides H 1560 and the cover guides H 1902 , described above, and fixed thereto by engaging portions H 1930 ( FIGS. 10B and 11 ) and so on for fixing the recording heads H 1001 and H 1002 to the recording apparatus.
  • the carriage 102 is supported along guide shafts 103 extending in the main scanning direction on the apparatus main body so as to reciprocate.
  • the recording heads H 1001 and H 1002 are mounted on the carriage 102 such that the arranging direction of the discharge ports (the direction along the discharge port arrays) crosses the scanning direction of the carriage 102 .
  • the recording heads H 1001 and H 1002 eject liquid from the discharge port arrays onto a recording medium 108 conveyed to a position facing the discharge ports by pickup rollers 131 and a conveying roller 109 serving as conveying devices for the recording medium 108 .
  • Reference numeral 101 denotes a recovery mechanism, which has a cap member for use in protecting the discharge-port formed surfaces of the recording heads H 1001 and H 1002 and sucks ink from the discharge ports of the recording heads H 1001 and H 1002 to recover the recording heads H 1001 and H 1002 to an ejectable state.
  • the cap member can be set at joined and separated positions to/from the discharge-port formed surface by a motor (not shown). In the joined state, a negative pressure is generated inside the cap member by a suction pump or the like (not shown) so that recording-head suction-recovery operation is performed. Also while the recording apparatus is not in use, the discharge-port formed surfaces of the recording heads H 1001 and H 1002 can be protected by setting the cap member in its joined state.
  • a recording apparatus in which the recording heads H 1001 and H 1002 are detachably mounted on the carriage 102 , a recording element substrate that constitutes a recording head and the carriage 102 may be integrated, and only an ink tank may be detachably mounted.
  • the recording heads according to the embodiments of the present invention may be applied to common printers that eject ink for printing, copying machines, facsimile machines having a communication system, and multifunctional recording apparatuses having the functions of such machines. Furthermore, the recording heads according to the embodiments of the present invention may be applied to apparatuses that eject liquid other than ink to draw figures or patterns on a recording medium.

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  • Particle Formation And Scattering Control In Inkjet Printers (AREA)
  • Ink Jet (AREA)
US12/416,844 2008-04-01 2009-04-01 Liquid discharge head and recording apparatus having the same Active 2030-02-11 US8033652B2 (en)

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JP6376731B2 (ja) * 2012-08-10 2018-08-22 キヤノン株式会社 液体吐出ヘッド及び液体吐出装置
JP5991179B2 (ja) * 2012-12-10 2016-09-14 セイコーエプソン株式会社 液体噴射ヘッド、及び、液体噴射装置
CN105939863B (zh) * 2014-01-30 2018-06-15 惠普发展公司，有限责任合伙企业 三色墨盒壳体
WO2015116113A1 (en) * 2014-01-30 2015-08-06 Hewlett-Packard Development Company, L.P. Tri-color ink cartridge
JP6472290B2 (ja) 2015-03-23 2019-02-20 キヤノン株式会社 液体吐出ヘッド及びその製造方法
JP7044492B2 (ja) * 2017-07-10 2022-03-30 エスアイアイ・プリンテック株式会社 流路部材、液体噴射ヘッド及び液体噴射装置

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CN101549585B (zh) 2011-07-20
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JP2009248328A (ja) 2009-10-29
US20090244181A1 (en) 2009-10-01

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